But not everybody is evil. So, you get together with lots of other people at a conference, and you announce a new code-of-conduct based organization to do mutual interconnection for homeservers that agree to a particular set of rules. The requirement for federation is that they agree, and that they will not federate with anyone who doesn't agree to the same set; the only penalty for non-compliance is not being allowed to federate with the members of the organization anymore.

There you go. Remember to thank the Matrix people for all their hard work, which you have subverted from "evil" to "good".